The objective of this contract is to examine the prechronic toxicity of butylbenzyl phthalate, to conduct a two year carcinogenicity study of diethyl phthalate, and conduct a 52 week initiation-promotion study of diethyl and dimethyl phthalate. The prechronic toxicity studies of butylbenzyl phthalate were conducted by administering the compound in the diet to groups of male and female F344 rats for 180 days. The two year study of diethyl phthalate is being conducted by administering the compound dermally to groups of male and female F344 rats and B6C3F1 mice for 103 weeks. The 52 week initiation-promotion study is being conducted with male swiss mice arranged into various treatment groups which receive vehicle, initiator, promotor, or both initiator and promotor.